The structures responsible for the growth of bones include the physis (also called growth plate) and the epiphysis. Affections involving patients with immature skeletons, i.e., with a still open growth plate, may affect the bone growth, resulting in complications such as growth arrest, limb shortening and angular deformities. Traumatic conditions, many times resulting in epiphyseal fractures, are the most frequent cause of growth plate injuries. A careful evaluation of these patients by means of currently available imaging methods, especially radiography, computed tomography and magnetic resonance imaging, allows an early diagnosis of the involvement of structures related to the bone growth, besides an appropriate management, reducing the probability of secondary complications.

Keywords: Growth plate, Fracture, Physeal bar, Bone bridge, Magnetic resonance imaging, Radiography, Computed tomography

OBJECTIVE: To evaluate the usefulness of combining static and kinematic magnetic resonance imaging in the evaluation of the femoropatellar joint. MATERIALS AND METHODS: Twenty healthy volunteers (40 knees) and 23 patients (43 knees) were submitted to both static and kinematic magnetic resonance imaging on a 1.5 tesla whole-body magnetic resonance scanner. The knees were positioned at 30º flexion with the quadrature knee coil at the inner end of the examination table. The patellar translation was evaluated by measurements of bisect offset, lateral patellar displacement and patellar tilt angle. The nonparametric Wilcoxon test was utilized for statistical analysis of data resulting from the static and kinematic studies in both groups. Nonparametric Mann-Whitney test was utilized in the comparison between healthy volunteers and patients. RESULTS: Statistical analysis demonstrated significant differences (p < 0.05) between static and kinematic magnetic resonance imaging for the three parameters evaluated in both groups. Among the patients the differences between static and kinematic measurements were greater than those found in the volunteers, at 30° and 20° flexion, with bisect offset and lateral patellar displacement. CONCLUSION: Static and kinematic magnetic resonance imaging, when performed in association, demonstrated that the lateral forces being exerted on the patella are higher at a knee flexion at the range between 20° and 30°, particularly in individuals symptomatic for femoropatellar instability.

Keywords: Knee, Knee joint, Patella, Patellofemoral pain syndrome, Magnetic resonance imaging, Biomechanics, Chondromalacia patellae

The iliopsoas compartment, a posterior boundary of the retroperitoneum, is comprised of the psoas major, psoas minor and iliac muscles. The symptoms picture in patients presenting with pathological involvement of this compartment may show a wide range of nonspecific clinical presentations that may lead to delayed diagnosis. However, in the search of an etiological diagnosis, it is already known that inflammation, tumors, and hemorrhages account for almost all the lesions affecting the iliopsoas compartment. By means of a retrospective analysis of radiological studies in patients with iliopsoas compartment lesions whose diagnosis was confirmed by anatomopathological evaluation or clinical follow-up, we have reviewed its anatomy as well as the main forms of involvement, with the purpose of identifying radiological signs that may help to narrow down the potential differential diagnoses. As each lesion is approached we will discuss the main radiological findings such as presence of gas in pyogenic abscesses, bone destruction and other bone changes of vertebral bodies in lesions secondary to tuberculosis, involvement of fascial planes in cases of neoplasms, and differences in signal density and intensity of hematomas secondary to hemoglobin degradation, among others. So, we have tried to present cases depicting the most frequent lesions involving the iliopsoas compartment, with emphasis on those signs that can lead us to a more specific etiological diagnosis.

Keywords: Iliopsoas muscle, Psoas muscle, Computed tomography, Abscesses, Neoplasms

OBJECTIVE: To compare the performance of low-field-strength and high-field-strength magnetic resonance imaging equipments for evaluation of the patella articular cartilage. MATERIALS AND METHODS: The study was developed using GRE 2D, GRE 3D, FSE T2, STIR sequences (low-field) and TSE T2 SPIR sequence. Each sequence has been separately analyzed for evaluation of the cartilage without knowledge of other sequences results or any patients data; the lesion was assigned a grade from 0 to 3 and had its location defined. Agreement and disagreement results were analyzed by Kappa and McNemar tests. RESULTS: Medial facet has presented low agreement index and disagreements showed to be significantly overestimated. Lateral facet has presented a reasonable agreement index and disagreement index was not significant. Medial ridge has presented a reasonable agreement index and disagreement index has showed to be underestimated. CONCLUSION: The STIR sequence versus TSE T2 SPIR sequence has presented the higher agreement index. High grade lesions are better characterized by low-field-strength magnetic resonance imaging equipment sequences. Areas of increased signal intensity make difficult the study of the patella medial facet cartilage in low-field-strength equipment.

Keywords: Magnetic resonance imaging, Skeletal - appendicular, Knee, Comparative study, Equipments, Imaging sequences

Several lesions may cause metatarsalgia whose clinical manifestations may be non-specific. Magnetic resonance imaging associated with other imaging methods and clinical data frequently can contribute to detection of these lesions, allowing a reasonably precise diagnosis to be considered. Our purpose is to describe and illustrate, by means of magnetic resonance imaging, main diseases causing metatarsalgia.

Keywords: Metatarsalgia, Foot diseases, Arthropathy, Magnetic resonance imaging

OBJECTIVE: To assess the usefulness of MRI as a diagnostic method in patients with rheumatoid arthritis, and to evaluate the frequency of changes in the hip in symptomatic and asymptomatic patients. MATERIALS AND METHODS: Forty patients (17 symptomatic and 23 asymptomatic) were evaluated by 1.5 T magnetic resonance imaging (MRI) after intravenous contrast media injection. MRI findings were divided in inflammatory, degenerative, combined (inflammatory and degenerative) and extra-articular changes. RESULTS: The most frequent findings seen were degenerative and extra-articular changes (22.5% each). Inflammatory changes were seen in only five (12.5%) symptomatic patients, four of them with degenerative findings associated (10%). CONCLUSION: The use of MRI of the hip allowed the evaluation of the main articular abnormalities seen in patients with rheumatoid arthritis. The most frequent findings were degenerative and extra-articular changes. Inflammatory findings were seen in only five patients, four of them with degenerative changes associated.

Keywords: Magnetic resonance imaging, Hip, Rheumatoid arthritis, Adult

Lipoma arborescens is an intraarticular lesion of unknown etiology, consisting of a chronic villous fat proliferation of the synovial membrane. The disease has occasionally been associated with diabetes mellitus, degenerative diseases, juvenile rheumatoid arthritis and also rheumatoid arthritis. The diagnosis relies on magnetic resonance imaging evaluation and synovial biopsy. We report a case of a 8-year-old girl with a two year history of bilateral swelling of the knees and elbows. The patient had improvement of the arthritis after starting treatment with conventional drugs.

Keywords: Lipoma arborescens, Juvenile rheumatoid arthritis, Magnetic resonance imaging

We report a case of a patient with primary cutaneous actinomycosis of the foot mimicking a soft tissue neoplasm. A literature review on the incidence, clinical features, pathology and imaging findings is also presented. The plain films and magnetic resonance imaging findings and the pathology results are presented. This paper reports a rare disease occurring in an atypical location, simulating a soft tissue neoplasm.

Keywords: Actinomycosis, Skin, Foot

Diagnostic imaging is crucial to the diagnosis and monitoring of spondyloarthropathies. Magnetic resonance imaging is the most relevant tool for the early detection of sacroiliitis, allowing the institution of therapeutic strategies to impede the progression of the disease. This study illustrates the major criteria for a magnetic resonance imaging-based diagnosis of spondyloarthropathy. The cases selected here present images obtained from the medical records of patients diagnosed with sacroiliitis over a two-year period at our facility, depicting the active and chronic, irreversible forms of the disease. Although computed tomography and conventional radiography can also identify structural changes, such as subchondral sclerosis, erosions, fat deposits, and ankylosis, only magnetic resonance imaging can reveal active inflammatory lesions, such as bone edema, osteitis, synovitis, enthesitis, and capsulitis.

Keywords: Sacroiliitis; Magnetic resonance imaging; Spondyloarthropathies; Ankylosing spondylitis; Computed tomography; Radiography.